The present research will be a continuation of our investigation into platelet prostaglandin, platelet calcium metabolism and its relationship to platelet function. We will continue to observe the function of the thrombocytopenic canine model and will pursue this in the future. The research will also accomplish platelet transfusion research in the canine model. We will also be studying platelet physiology of patients with acute leukemia. BIBLIOGRAPHIC REFERENCES: Gerrard, J.M., White, J.G., & Krivit, W.: Labile aggregation stimulating substance, free fatty acids, and platelet aggregation. J. Lab. Clin. Med.; 87: 73 - 82, January, 1976. Balfanz, J.R., Nesbit, M.E., & Krivit, W.: Overwhelming Sepsis following Splenectomy for Trauma. J. of Peds. 88:458, March, 1976.